In the increasingly competitive market, higher and higher requirements on the energy density of softly-packaged lithium ion batteries have been proposed by various electronic products. To enhance the market competitiveness, it is desirable for manufacturers to reduce the production cost of softly-packaged lithium ion batteries as much as possible. To increase the energy density of batteries ad reduce the production cost simultaneously, a single-folding rubber coating procedure may be replaced with a double-folding rubber coating procedure.
However, the double-folding rubber coating procedure has a very high precision requirement on the arrangement of a station for the bonding layer. This station is required to have precise glue dispensing positions and strict glue volume control. The offset of a glue dispensing position will cause the risk of unfolding or glue overflow due to the insecure bonding between the secondarily folded edge and the battery cell body. Excessive glue volume will cause the risk of glue overflow, while inadequate glue volume will cause the risk of unfolding due to the insecure bonding between the secondarily folded edge and the battery cell body. During the automatic production, the slight deviation of glue dispensing positions and glue volume will result in a large batch of defective products. However, the desired precision cannot be achieved as both the glue dispensing position and glue volume of double-folding equipment in the current market are artificially monitored. As a result, the reject rate is increased. Furthermore, a large amount of manpower is consumed, and the production cost is increased.